Interfacial Engineering of Polyphenylene Sulfide Fiber Membrane for High-Performance Alkaline Water Electrolysis

Abstract

Membranes are critical components for the stable operation of alkaline water electrolysis (ALK). Conventional polyphenylene sulfide (PPS) fiber membranes exhibit excellent thermal and chemical stability. However, the hydrophobicity of the surface and the large pores of the fabric structure cause voltage increase and gas crossover, which significantly affects the power consumption and safety of ALK. Therefore, the development of membranes with both high ionic conductivity and excellent gas barrier performance has become a key breakthrough in improving the efficiency of ALK. Herein, polydopamine was polymerized in situ on the surface of PPS fiber membrane by introducing CuSO4/H2O2 to strengthen the crosslinking system. The hydrophilicity of the PPS fiber membrane surface was improved while reducing the pore size of the fiber fabric. In membrane electrode assembly testing, polydopamine-modified PPS (P-PPS) fiber membrane achieved a voltage of 2.03 V@600 mA cm-2 in 30wt% KOH solution at 80°C. Furthermore, P-PPS fiber membrane used for ALK was stabilized for 200 h at 500 mA cm-2 with a voltage loss of only 0.1 V. The gas purity test showed an excellent gas barrier capability, where the purity of hydrogen and oxygen produced was 99.870% and 99.193% at a current density of 1.0 A cm-2, respectively. The above results indicate that the P-PPS fiber membrane prepared has great application prospects in industrialized production in ALK.